Mark Sanchez does not feel comfortable enough to take a snap - but one step at a time.

USC's backup quarterback finally threw a football Wednesday, 24 days after suffering a hairline fracture in his right thumb, during the Trojans' first preseason scrimmage. The redshirt sophomore participated in positional drills and seven-on-sevens, completing 80 percent of his passes against the defense, he said.

His arm looked strong, as usual. The biggest challenge will be mental.

"If anything, I'm a little tentative, just to slap hands with anybody, to do anything too crazy," Sanchez said. "Even when I drive my car, turn the keys, I'm always doing it with my left hand. I'm opening doors with my left hand.